This application claims the priority benefit of Taiwan application serial no. 90109366, filed Apr. 19, 2001.
1. Field of the Invention
The present invention relates to a tape shifting means. More specifically, the present invention relates to a tape shifting means which changes the way to contact the heads of the shifting means with tape in order to decrease the amount of film left on the head.
2. Description of the Related Art
Liquid crystal was found by Reinitzer, who was an Austrian plant researcher, in 1888. Attempts to develop liquid crystal as a material for a display device have been made since transparent liquid crystal was found to turn opaque if an electric field is applied. A liquid crystal display (LCD) has various superior advantages, such as non-radiation and low driving voltage, and can be used in related electronic products, such as a notebook computer or a liquid crystal television. However, a plurality of driving chips with tape carrier packages (TCPs) need to be provided around the LCD to electrically connect the chips to the LCD. For TCP, a carrier is provided to support a plurality of inner leads for electrically connecting to the driving chips and a plurality of outer leads for electrically connecting to the LCD. There are various ways to connect the outer leads to the LCD, including welding or anisotropic conductive film attachment. The anisotropic conductive film is a resin having conductive fine powders distributed therein. The conductive fine powders can be formed of materials such as nickel, solder or carbon. When the outer leads are connected to the LCD by an anisotropic conductive film attachment, the anisotropic conductive film is pressed on contacts of the liquid crystal sheet and heated until the anisotropic conductive film is melted. Then, the anisotropic conductive film is pressed against the outer leads. With the conductive powders distributed in the anisotropic conductive film, the outer leads can be electrically connected to the connections.
FIG. 1 is a schematic view showing a conventional anisotropic conductive film. The anisotropic conductive film 20 is carried by a tape 30, with the bottom surface 32 of the tape 30 keeping contact with the anisotropic conductive film 20. The tape 30 is conveyed forward by a shifting means 40. A cutter (not shown) is used to partly cut the anisotropic conductive film 20 into a plurality of sections that are not discrete. Each of the sections can match the connections on the liquid crystal sheet 60. When the section of the anisotropic conductive film 20 are above the connections on the liquid crystal sheet, a pressing member 50 presses the anisotropic conductive film 20 down to bond the anisotropic conductive film 20 to the connection and leave the non-bonded portion of the anisotropic film 20 on the tape 30. Then, the pressing member 50 is removed. The portion of the remained anisotropic film 20 goes forward with the tape 30 for a predetermined distance by the shifting means 40 and winds around a reel (not shown).
FIG. 2 is a front view of a conventional tape shifting means. FIG. 3 is a side view of the conventional tape shifting means of FIG. 2.
With reference to FIGS. 2 and 3, a shifting means 100 includes a first head 110 and a second head 120. The first head 110 has a first surface 112 to contact with a tape 130. The second head 120 has a second surface to contact with the tape 130.
When the shifting means clamps the tape 130, the anisotropic conductive film remained on the tape 130 can adhere to the second surface 122 of the second head 120. Even though the second surface 122 has a Teflon coating thereon, it cannot effectively prevent the anisotropic conductive film from adhering to the second surface 122. Furthermore, the Teflon coating on the second surface 122 would be damaged after it is used for a certain period, and a new shifting means is needed. If the shifting means having a damaged surface is not replaced, a poor yield is obtained.
In one aspect of the present invention, a tape shifting means is provided, in which the tape shifting means changes the way to contact heads of the shifting means with tape to decrease the amount of film left on the head.
In order to achieve the above and other objects of the present invention, a tape shifting means is provided, in which the tape shifting means can convey a tape carrying the conductive film and separate an anisotropic conductive film from the tape. The shifting means includes a first head having a first surface and a second head having a second surface. The first head contacts with the top of the tape by the first surface of the first head. The second head contacts with the bottom of the tape by the second surface of the second head. The first surface is further provided with a plurality of first projections thereon The second surface is further provided with a plurality of second projections. All of the first projections and the second projections can be shaped into strips, such that the top surface of the first projection is parallel to the first surface and the top surface of the second projection is parallel to the second surface. When the first head and the second head come into contact with the tape, the first projection is perpendicular to the second projection such that pressed regions of the tape which are pressed by both the first head and the second head are distributed in an array.
In the present invention, the shifting means changes the way to contact the heads of the shifting means with tape to decrease the amount of film left on the head. Therefore, the contact area between the second surface and the tape is reduced greatly and the amount of the anisotropic conductive film which is left on the second surface thus can be decreased, thereby increasing the yield and the service life of the shifting means.